Comment 4 for bug 1639558

Patch has been committed to upstream git that fixes the problem with "N: Ignoring file '50unattended-upgrades.ucf-dist' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension"

https://anonscm.debian.org/git/apt/apt.git/commit/?id=5094697fe4b2459ff6f706a22006d3028369f3fa